Grate in the frozen butter using the large holes of a standard box grater and toss quickly to thoroughly coat with flour.

Sprinkle in the ice water then stir until a dough forms. Knead the dough just a few times as needed to bring everything together.

Immediately roll it out thinly – about 1/4 inch thick – and cut out 12 circles.

Fit them into a lightly oiled muffin tin.

Brown the butter by placing it in a saucepan over medium heat, heating and melting it until it begins to steam and foam.

Keep a close eye on it as it foams. Swirl it gently, watching the color. When it turns golden brown and releases the aroma of toasting nuts, immediately remove it from the heat and whisk in the maple syrup, brown sugar, eggs and vanilla.

Add the flour and stir to combine. Put together and bake for 10-12 minutes.

In large bowl, cream butter with sugar until fluffy; beat in egg yolk and vanilla. Stir together flour, cornstarch and salt; gradually stir into creamed mixture; gently kneading until smooth.

Working in batches, gently form dough into 3/4 inch (2 cm) balls, place in 1 1/2 inch (4 cm) tart cups and press evenly over bottom and sides of cup to form shell.

Bake in 325 ° F (160 ° C) oven for about 18 minutes or until crisp and pale golden. Let cool in pan on rack; loosen shells with tip of knife.

Filling

In a small saucepan, bring dates, sugar, water and salt to boil over medium heat; reduce heat and simmer; stirring often, for 4 minutes or until thickened and smooth. Let cool, stir in vanilla. Spoon into shells.

Icing

Blend together icing sugar, maple syrup and butter until smooth; dollop onto each tart. (Tarts can be stored at room temperature for up to 4 days or frozen for up to 2 weeks.)